The use of electric power-steering apparatuses is widely spread as a steering apparatus for applying a steering angle to the steered wheels of an automobile, and that uses an electric motor as a drive source to reduce the steering force. FIG. 14 illustrates an example of a conventional electric power-steering apparatus that is disclosed in JP 2011-131682 (A). In this structure, the rotation of a steering wheel 1 is transmitted to an input shaft 3 of a steering gear unit 2, and as the input shaft 3 rotates, a pair of left and right tie rods 4 are pushed or pulled, which applies a steering angle to steered wheels. The steering wheel 1 is supported by and fastened to the rear end section of a steering shaft 5, and this steering shaft 5 is inserted in the axial direction through a cylindrical steering column 6, and supported by this steering column 6 so as to be able to freely rotate. Moreover, the front end section of the steering shaft 5 is connected to the rear end section of an intermediate shaft 8 by way of a universal joint 7a, and the front end of this intermediate shaft 8 is connected to the input shaft 3 by way of another universal joint 7b. The forward-backward direction and the width direction in this specification mean the forward-backward direction and the width direction of the vehicle when the steering apparatus is assembled in the vehicle, and left and right in the width direction means the left and right with respect to the direction of travel when the vehicle is traveling in the forward direction.
The front end section of the steering column 6 is connected to a housing 9 of the electric power-steering apparatus. Component parts of the electric power-steering apparatus such as a torque detector, a worm reduction gear and the like are housed inside this housing 9, and an electric motor 10, which is an auxiliary power source of the electric power-steering apparatus, is supported by the outside surface of this housing 9. Moreover, in order to construct a tilt mechanism for adjusting the height position of the steering wheel 1, the housing 9 is supported by the vehicle body 11 so as to be able to pivotally displace around a pivot shaft 12 that is arranged in the width direction of the vehicle, and the a portion on the rear side of the intermediate section of the steering column 6 is supported by a rear support bracket 13 that is supported by the vehicle body 11 such that the up-down position can be adjusted. In regards to the detailed structure of this tilt mechanism, various kinds of structures are known, and because the adjustment mechanism for adjusting the up-down position with respect to the rear support bracket 13 is not related to the main feature of the present invention, detailed drawings and explanations are omitted.
As described above, in order to construct an electric power-steering apparatus that comprises a tilt mechanism, the housing 9 that is connected to the front end section of the steering column 6 must be supported by the vehicle body 11 so as to be able to pivotally displace around a pivot shaft 12 that is arranged in the width direction. Therefore, it is necessary that a support bracket 14 be fastened to the vehicle body 11, and that this support bracket 14 and housing 9 be connected by the pivot shaft 12. The support bracket 14 supports the front end section of the steering column 6 by way of the housing 9 in or to which the component parts of the electric power-steering apparatus are housed or mounted, so it is necessary that the strength and rigidity of the support bracket 14 be sufficiently large. On the other hand, in order to suppress manufacturing costs of an electric power-steering apparatus that comprises a tilt mechanism, preferably this support bracket 14 is made by using a press to punch and bend a metal plate such as steel plate having the required strength and rigidity, such as disclosed in JP 2005-219641 (A). However, when trying to make the support bracket 14 using a metal plate, while at the same time maintain the required strength and rigidity, the cutting stock is insufficient, and it is easy for the metal plate material to be wasted. In order to keep the manufacturing costs of the support bracket 14 low, it is necessary to effectively use the metal plate and to improve the material yield. However, a support bracket made using a metal plate having structure that can meet these needs has not been achieved yet.